Arab-plan or hypostyle mosques are the earliest type of mosques, pioneered under the Umayyad Dynasty. These mosques are square or rectangular in plan with an enclosed courtyard and a covered prayer hall. Historically, because of the warm Mediterranean and Middle Eastern climates, the courtyard served to accommodate the large number of worshipers during Friday prayers. Most early hypostyle mosques have flat roofs on top of prayer halls, necessitating the use of numerous columns and supports.
One of the most notable hypostyle mosques is the Mezquita in Córdoba, Spain, as the building is supported by over 850 columns. Frequently, hypostyle mosques have outer arcades so that visitors can enjoy some shade. Arab-plan mosques were constructed mostly under the Umayyad and Abbasid dynasties; subsequently, however, the simplicity of the Arab plan limited the opportunities for further development, and as a result, these mosques gradually fell out of popularity.
The Ottomans introduced central dome mosques in the 15th century and have a large dome centered over the prayer hall. In addition to having one large dome at the center, there are often smaller domes that exist off-center over the prayer hall or throughout the rest of the mosque, where prayer is not performed. This style was heavily influenced by the Byzantine religious architecture with its use of large central domes.
